8 / 2021-06-07 17:05:53

In-situ alumina particle reinforced high-entropy composite coating and its anti-friction performance

high-entropy,composite coating,wear resistance,friction

Effect of Al content on the microstructure and wear resistance of in-situ alumina particle reinforced high-entropy alloy composite coating was studied. Laser cladding technology was used to prepare Al_xCoCrFeNi (x=0, 0.3, 1, 1.5, 2) high-entropy alloy composite coating with in-situ Al₂O₃ ceramic particles on the surface of Q235 steel using thermite reaction method. XRD, SEM, EDS, friction test, XPS, RAMAN and other experimental methods were used to study the microstructure and wear resistance of the high-entropy alloy composite coatings. There are dispersed nano-sized Al₂O₃ ceramic particles in the coating. With the increase of Al content, the microstructure of the high-entropy alloy composite coating gradually changes from FCC and BCC coexistence to BCC single phase microstructure. In the friction and wear test, the friction coefficient and wear rate of the coating under low load are significantly reduced. Increasing the Al element in the composite coating can stabilize the BCC phase and refine the structure. At the same time, excessive Al element can inhibit Fe element oxidation and increase the content of Fe₃O₄ on the surface of the wear scar, thereby significantly reducing the friction coefficient of the composite coating and improving its wear resistance. Al₂CoCrFeNi has the lowest friction coefficient (0.15) and the lowest wear rate (1.01×10^-6mm³/N﹒m), which are 1/4 and 1/38 of the matrix respectively, showing excellent tribological properties.